Discrete time cancellation for providing coexistence in radio frequency applications

ABSTRACT

Radio frequency (RF) communication systems with coexistence management are provided herein. In certain embodiments, a method of coexistence management in a mobile device includes processing a wireless local area network (WLAN) observation signal to generate WLAN observation data using a WLAN observation channel of a WLAN transceiver, processing an RF cellular receive signal to generate a digital baseband cellular receive signal using a cellular receive channel of a cellular transceiver, processing a cellular observation signal to generate cellular observation data using a cellular observation channel of the cellular transceiver, and compensating the digital baseband cellular receive signal for RF signal leakage based on the WLAN observation data and on the cellular observation data using a discrete time cancellation circuit of the cellular transceiver.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.17/650,768, filed Feb. 11, 2022, and titled “DISCRETE TIME CANCELLATIONFOR PROVIDING COEXISTENCE IN RADIO FREQUENCY COMMUNICATION SYSTEMS,”which is a continuation of U.S. application Ser. No. 16/949,388, filedOct. 28, 2020, and titled “DISCRETE TIME CANCELLATION FOR PROVIDINGCOEXISTENCE IN RADIO FREQUENCY COMMUNICATION SYSTEMS,” which claimspriority to U.S. application Ser. No. 16/541,530, filed Aug. 15, 2019,and titled “DISCRETE TIME CANCELLATION FOR PROVIDING COEXISTENCE INRADIO FREQUENCY COMMUNICATION SYSTEMS,” which claims the benefit ofpriority under 35 U.S.C. § 119 of U.S. Provisional Patent ApplicationNo. 62/720,514, filed Aug. 21, 2018, and titled “DISCRETE TIMECANCELLATION FOR PROVIDING COEXISTENCE IN RADIO FREQUENCY COMMUNICATIONSYSTEMS,” each of which is herein incorporated by reference in itsentirety.

BACKGROUND Field

Embodiments of the invention relate to electronic systems, and inparticular, to radio frequency electronics.

Description of Related Technology

Radio frequency (RF) communication systems can be used for transmittingand/or receiving signals of a wide range of frequencies. For example, anRF communication system can be used to wirelessly communicate RF signalsin a frequency range of about 30 kHz to 300 GHz, such as in the range ofabout 410 MHz to about 7.125 GHz for fifth generation (5G) frequencyrange 1 (FR1) communications.

Examples of RF communication systems include, but are not limited to,mobile phones, tablets, base stations, network access points,customer-premises equipment (CPE), laptops, and wearable electronics.

SUMMARY

In certain embodiments, the present disclosure relates to a mobiledevice. The mobile device includes a first front end system configuredto output a radio frequency receive signal and a first radio frequencyobservation signal, and a first transceiver including a receive channelconfigured to process the radio frequency receive signal to generate afirst digital baseband receive signal, a first observation channelconfigured to process the first radio frequency observation signal togenerate a first digital observation signal, a first spectral regrowthbaseband sampling circuit configured to process the first digitalobservation signal to generate spectral regrowth observation data, and adiscrete time cancellation circuit configured to compensate the firstdigital baseband receive signal for radio frequency signal leakage basedon the spectral regrowth observation data and on direct transmit leakageobservation data.

In some embodiments, the mobile device further includes a secondtransceiver configured to provide the direct transmit leakageobservation data to the first transceiver.

According to various embodiments, the second transceiver includes asecond observation channel configured to process a second radiofrequency observation signal to generate a second digital observationsignal, and a direct transmit leakage baseband sampling circuitconfigured to process the second digital observation signal to generatethe direct transmit leakage observation data. In accordance with anumber of the embodiments, the mobile device further includes a secondfront end system configured to output the second radio frequencyobservation signal and a radio frequency transmit signal. According toseveral embodiments, the first front end system includes a firstdirectional coupler configured to generate the first radio frequencyobservation signal, and the second front end system includes a seconddirectional coupler configured to generate the second radio frequencyobservation signal. In accordance with various embodiments, the mobiledevice further includes a first antenna coupled to the first front endsystem and a second antenna coupled to the second front end system, thefirst directional coupler configured to generate the first radiofrequency observation signal based on a reverse coupled path to thefirst antenna, and the second directional coupler configured to generatethe second radio frequency observation signal based on a forward coupledpath to the second antenna. According to a number of embodiments, thedirect transmit leakage observation data indicates an amount of directtransmit leakage present in the radio frequency transmit signal. Inaccordance with several embodiments, the first transceiver is a cellulartransceiver and the second transceiver is a WiFi transceiver. Accordingto a number of embodiments, the first transceiver is a WiFi transceiverand the second transceiver is a cellular transceiver. In accordance withvarious embodiments, the second transceiver includes a discrete timecancellation circuit configured to compensate a second digital basebandreceive signal for radio frequency signal leakage.

In some embodiments, the spectral regrowth observation data indicates anamount of aggressor spectral regrowth present in the radio frequencyreceive signal.

In a number of embodiments, the first front end system includes a firstdirectional coupler configured to generate the first radio frequencyobservation signal.

In several embodiments, the mobile device further includes a firstantenna coupled to the first front end system, and the first directionalcoupler is configured to generate the first radio frequency observationsignal based on a reverse coupled path to the first antenna. Accordingto various embodiments, the first front end system includes a duplexer,and the first directional coupler is positioned between an output of theduplexer and the first antenna. In accordance with a number ofembodiments, the first front end system includes a duplexer and a poweramplifier, and the first directional coupler is positioned between anoutput of the power amplifier and an input to the duplexer.

In certain embodiments, the present disclosure relates to a transceiver.The transceiver includes a receive channel configured to process a radiofrequency receive signal to generate a digital baseband receive signal,a first observation channel configured to process a first radiofrequency observation signal to generate a first digital observationsignal, a spectral regrowth baseband sampling circuit configured toprocess the first digital observation signal to generate spectralregrowth observation data, and a discrete time cancellation circuitconfigured to compensate the digital baseband receive signal for radiofrequency signal leakage based on the spectral regrowth observation dataand on direct transmit leakage observation data.

In a number of embodiments, the spectral regrowth observation dataindicates an amount of aggressor spectral regrowth present in the radiofrequency receive signal.

In various embodiments, the direct transmit leakage observation dataindicates an amount of direct transmit leakage present in an aggressorradio frequency transmit signal.

In several embodiments, the transceiver is configured to receive thedirect transmit leakage observation data from another transceiver.

In some embodiments, the transceiver is implemented as cellulartransceiver.

In a number of embodiments, the transceiver is implemented as WiFitransceiver.

In various embodiments, the transceiver further includes a secondobservation channel configured to process a second radio frequencyobservation signal to generate a second digital observation signal, anda first direct transmit leakage baseband sampling circuit configured toprocess the second digital observation signal to generate first transmitleakage observation data.

According to a number of embodiments, the transceiver is configured tooutput the first transmit leakage observation data to anothertransceiver.

In accordance with several embodiments, the transceiver further includesa second direct transmit leakage baseband sampling circuit configured toprocess a third digital observation signal to generate second transmitleakage observation data, and an observation switch configured toselectively provide the first transmit leakage observation data or thesecond transmit leakage observation data as an output of thetransceiver. According to various embodiments, the transceiver furtherincludes a third observation channel configured to process a third radiofrequency observation signal to generate the third digital observationsignal. In accordance with a number of embodiments, the transceiverfurther includes a transmit power control circuit configured to receivesecond digital observation signal.

In certain embodiments, the present disclosure relates to a method ofcoexistence management in a mobile device. The method includesprocessing a radio frequency receive signal to generate a digitalbaseband receive signal using a receive channel of a first transceiver,processing a first radio frequency observation signal to generate afirst digital observation signal using a first observation channel ofthe first transceiver, generating spectral regrowth observation databased on processing process the first digital observation signal using afirst spectral regrowth baseband sampling circuit of the firsttransceiver, and compensating the digital baseband receive signal forradio frequency signal leakage based on the spectral regrowthobservation data and on direct transmit leakage observation data using adiscrete time cancellation circuit of the first transceiver.

In some embodiments, the spectral regrowth observation data indicates anamount of aggressor spectral regrowth present in the radio frequencyreceive signal.

In various embodiments, the direct transmit leakage observation dataindicates an amount of direct transmit leakage present in an aggressorradio frequency transmit signal.

In several embodiments, the method further includes receiving the directtransmit leakage observation data from a second transceiver. Accordingto a number of embodiments, the first transceiver is a cellulartransceiver and the second transceiver is a WiFi transceiver. Inaccordance with various embodiments, the first transceiver is a WiFitransceiver and the second transceiver is a cellular transceiver.

In some embodiments, the method further includes processing a secondradio frequency observation signal to generate a second digitalobservation signal using a second observation channel of the firsttransceiver, and processing the second digital observation signal togenerate leakage observation data using a direct transmit leakagebaseband sampling circuit of the first transceiver. According to severalembodiments, the method further includes providing the leakageobservation data from the first transceiver to a second transceiver.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of one example of a mobile devicecommunicating via cellular and WiFi networks.

FIG. 2 is a schematic diagram of one example of signal leakage for an RFcommunication system.

FIG. 3A is a schematic diagram of one example of direct transmit leakagefor an RF communication system.

FIG. 3B is a schematic diagram of one example of regrowth leakage for anRF communication system.

FIG. 4A is a schematic diagram of an RF communication system withcoexistence management according to one embodiment.

FIG. 4B is a schematic diagram of an RF communication system withcoexistence management according to another embodiment.

FIG. 5 is a schematic diagram of an RF communication system withcoexistence management according to another embodiment.

FIG. 6 is a schematic diagram of an RF communication system withcoexistence management according to another embodiment.

FIG. 7 is a schematic diagram of an RF communication system withcoexistence management according to another embodiment.

FIG. 8 is a schematic diagram of one embodiment of a mobile device withcoexistence management.

FIG. 9A is a schematic diagram of one embodiment of a packaged modulewith coexistence management.

FIG. 9B is a schematic diagram of a cross-section of the packaged moduleof FIG. 9A taken along the lines 9B-9B.

DETAILED DESCRIPTION OF EMBODIMENTS

The following detailed description of certain embodiments presentsvarious descriptions of specific embodiments. However, the innovationsdescribed herein can be embodied in a multitude of different ways, forexample, as defined and covered by the claims. In this description,reference is made to the drawings where like reference numerals canindicate identical or functionally similar elements. It will beunderstood that elements illustrated in the figures are not necessarilydrawn to scale. Moreover, it will be understood that certain embodimentscan include more elements than illustrated in a drawing and/or a subsetof the elements illustrated in a drawing. Further, some embodiments canincorporate any suitable combination of features from two or moredrawings.

FIG. 1 is a schematic diagram of one example of a mobile device 2 acommunicating via cellular and WiFi networks. For example, as shown inFIG. 1 , the mobile device 2 a communicates with a base station 1 of acellular network and with a WiFi access point 3 of a WiFi network. FIG.1 also depicts examples of other user equipment (UE) communicating withthe base station 1, for instance, a wireless-connected car 2 b andanother mobile device 2 c. Furthermore, FIG. 1 also depicts examples ofother WiFi-enabled devices communicating with the WiFi access point 3,for instance, a laptop 4.

Although specific examples of cellular UE and WiFi-enabled devices isshown, a wide variety of types of devices can communicate using cellularand/or WiFi networks. Examples of such devices, include, but are notlimited to, mobile phones, tablets, laptops, Internet of Things (IoT)devices, wearable electronics, customer premises equipment (CPE),wireless-connected vehicles, wireless relays, and/or a wide variety ofother communication devices.

In certain implementations, UE, such as the mobile device 2 a of FIG. 1, is implemented to support communications using a number oftechnologies, including, but not limited to, 2G, 3G, 4G (including LTE,LTE-Advanced, and LTE-Advanced Pro), 5G NR, WLAN (for instance, WiFi),WPAN (for instance, Bluetooth and ZigBee), WMAN (for instance, WiMax),and/or GPS. In certain implementations, enhanced license assisted access(eLAA) is used to aggregate one or more licensed frequency carriers (forinstance, licensed 4G LTE and/or 5G NR frequencies), with one or moreunlicensed carriers (for instance, unlicensed WiFi frequencies).

Furthermore, certain UE can communicate not only with base stations andaccess points, but also with other UE. For example, thewireless-connected car 2 b can communicate with a wireless-connectedpedestrian 2 d, a wireless-connected stop light 2 e, and/or anotherwireless-connected car 2 f using vehicle-to-vehicle (V2V) and/orvehicle-to-everything (V2X) communications.

Although various examples of communication technologies have beendescribed, mobile devices can be implemented to support a wide range ofcommunications.

Various communication links have been depicted in FIG. 1 . Thecommunication links can be duplexed in a wide variety of ways,including, for example, using frequency-division duplexing (FDD) and/ortime-division duplexing (TDD). FDD is a type of radio frequencycommunications that uses different frequencies for transmitting andreceiving signals. FDD can provide a number of advantages, such as highdata rates and low latency. In contrast, TDD is a type of radiofrequency communications that uses about the same frequency fortransmitting and receiving signals, and in which transmit and receivecommunications are switched in time. TDD can provide a number ofadvantages, such as efficient use of spectrum and variable allocation ofthroughput between transmit and receive directions.

Different users of the illustrated communication networks can shareavailable network resources, such as available frequency spectrum, in awide variety of ways. In one example, frequency division multiple access(FDMA) is used to divide a frequency band into multiple frequencycarriers. Additionally, one or more carriers are allocated to aparticular user. Examples of FDMA include, but are not limited to,single carrier FDMA (SC-FDMA) and orthogonal FDMA (OFDMA). OFDM is amulticarrier technology that subdivides the available bandwidth intomultiple mutually orthogonal narrowband subcarriers, which can beseparately assigned to different users.

Other examples of shared access include, but are not limited to, timedivision multiple access (TDMA) in which a user is allocated particulartime slots for using a frequency resource, code division multiple access(CDMA) in which a frequency resource is shared amongst different usersby assigning each user a unique code, space-divisional multiple access(SDMA) in which beamforming is used to provide shared access by spatialdivision, and non-orthogonal multiple access (NOMA) in which the powerdomain is used for multiple access. For example, NOMA can be used toserve multiple users at the same frequency, time, and/or code, but withdifferent power levels.

Examples of Radio Frequency Systems with Coexistence Management

Radio frequency (RF) communication systems can include multipletransceivers for communicating using different wireless networks, overmultiple frequency bands, and/or using different communicationstandards. Although implementing an RF communication system in thismanner can expand functionality, increase bandwidth, and/or enhanceflexibility, a number of coexistence issues can arise between thetransceivers operating within the RF communication system.

For example, an RF communication system can include a cellulartransceiver for processing RF signals communicated over a cellularnetwork and a wireless local area network (WLAN) transceiver forprocessing RF signals communicated over a WLAN network, such as a WiFinetwork. For instance, the mobile device 2 a of FIG. 1 is operable tocommunicate using cellular and WiFi networks.

Although implementing the RF communication system in this manner canprovide a number of benefits, a mutual desensitization effect can arisefrom cellular transmissions interfering with reception of WiFi signalsand/or from WiFi transmissions interfering with reception of cellularsignals.

In one example, cellular Band 7 can give rise to mutual desensitizationwith respect to 2.4 Gigahertz (GHz) WiFi. For instance, Band 7 has anFDD duplex and operates over a frequency range of about 2.62 GHz to 2.69GHz for downlink and over a frequency range of about 2.50 GHz to about2.57 GHz for uplink, while 2.4 GHz WiFi has TDD duplex and operates overa frequency range of about 2.40 GHz to about 2.50 GHz. Thus, cellularBand 7 and 2.4 GHz WiFi are adjacent in frequency, and RF signal leakagedue to the high power transmitter of one transceiver/front end affectsreceiver performance of the other transceiver/front end, particularly atborder frequency channels.

In another example, cellular Band 40 and 2.4 GHz WiFi can give rise tomutual desensitization. For example, Band 40 has a TDD duplex andoperates over a frequency range of about 2.30 GHz to about 2.40 GHz,while 2.4 GHz WiFi has TDD duplex and operates over a frequency range ofabout 2.40 GHz to about 2.50 GHz. Accordingly, cellular Band 40 and 2.4GHz WiFi are adjacent in frequency and give rise to a number ofcoexistence issues, particularly at border frequency channels.

Desensitization can arise not only from direct leakage of an aggressortransmit signal to a victim receiver, but also from spectral regrowthcomponents generated in the transmitter. Such interference can lierelatively closely in frequency with the victim receive signal and/ordirectly overlap it. Although a receive filter can provide somefiltering of signal leakage, the receive filter may provide insufficientattenuation of the aggressor signal, and thus the sensitivity of thevictim receiver is degraded.

Conventional techniques alone are insufficient for providing mutualcoexistence. In one example, a very high quality-factor (high Q)bandpass filter (for instance, an acoustic bandpass filter) can beincluded at the output of a power amplifier of an aggressor transmitterto attenuate spectral regrowth. When the attenuation provided by thefilter is sufficiently high, the victim receiver may not besignificantly desensitized due to non-linearity of the aggressortransmitter. However, such high-Q bandpass filters can be prohibitivelyexpensive and/or introduce insertion loss that degrades transmitperformance.

In another example, a very high Q bandpass filter can be included on thevictim receiver to attenuate high power leakage coupled in from theaggressor transmitter. When the attenuation is sufficiently high, thevictim receiver is not significantly desensitized from coupling of thehigh power leakage into non-linear receive circuitry of the victimreceiver. However, such high-Q bandpass filters can be prohibitivelyexpensive and/or introduce insertion loss that degrades receiversensitivity.

RF communication systems with coexistence management are providedherein. In certain embodiments, a mobile device includes a firstantenna, a first front end system that receives an RF receive signalfrom the first antenna, a first transceiver coupled to the first frontend system, a second antenna, a second front end system that provides anRF transmit signal to the second antenna, and a second transceivercoupled to the second front end system. The first front end systemgenerates a first observation signal by observing the RF receive signal,and the second front end system generates a second observation signal byobserving the RF transmit signal. The first transceiver alsodownconverts the RF receive signal to baseband, and uses the firstobservation signal and the second observation signal to compensate thebaseband receive signal for RF signal leakage.

By implementing the mobile device in this manner, compensation forsignal leakage arising from signal coupling from the second antenna tothe first antenna is provided. Thus, the mobile device operates withenhanced receiver sensitivity when the first transceiver is receivingand the second transceiver is transmitting.

In certain implementations, the first transceiver/first front end systemcan process RF signals of a different type than the secondtransceiver/second front end system. In one example, the firsttransceiver/first front end system processes cellular signals while thesecond transceiver/second front end system processes WLAN signals, suchas WiFi signals. Accordingly, in certain implementations herein,coexistence management is provided between cellular and WiFi radios.

In certain implementations, the first observation signal indicatesspectral regrowth leakage and the second observation signal indicatesdirect transmit leakage. For example, the first observation signal caninclude extracted samples of aggressor regrowth, while the secondobservation signal can include extracted samples of aggressor directtransmit leakage. Accordingly, multiple components of RF signal leakagecan be compensated.

In certain implementations, the baseband receive signal is compensatedusing discrete time cancellation. For example, compensation can beprovided using a discrete time cancellation loop having multiple inputs.The cancellation loop can be adapted to reduce unwanted signalcomponents using any suitable cancellation algorithm, including, but notlimited to, a least mean squares (LMS) algorithm. In one embodiment, atransceiver includes a discrete time cancellation circuit including afinite impulse response (FIR) filter having coefficients adapted overtime to reduce or eliminate RF signal leakage.

The first observation signal and the second observation signal can begenerated in a wide variety of ways. In one example, the first front endsystem includes a first directional coupler along a first RF signal pathto the first antenna and the second front end system includes a seconddirectional coupler along a second RF signal path to the second antenna.Additionally, the first directional coupler generates the firstobservation signal based on sensing an incoming RF signal from the firstantenna, while the second directional coupler generates the secondobservation signal based on sensing an outgoing RF signal to the secondantenna. Thus, the first observation signal can be generated based on areverse coupled path of the first directional coupler, and the secondobservation signal can be generated based on a forward coupled path ofthe second directional coupler.

The second transceiver can also be implemented with circuitry forcompensating for RF signal leakage. For example, the first front endsystem can observe an outgoing transmit signal to the first antenna togenerate a third observation signal, and the second front end system canobserve an incoming receive signal to generate a fourth observationsignal. Additionally, the second transceiver downconverts the incomingreceive signal to generate a second baseband receive signal, which thesecond transceiver compensates for RF signal leakage based on the thirdobservation signal and the fourth observation signal. Accordingly, incertain implementations, both the first transceiver and the secondtransceiver operate with coexistence management.

In certain implementations, observation paths used for power control(for instance, transmit power control or TPC) and/or predistortioncontrol (for instance, digital predistortion or DPD) are also used forobservations of regrowth and/or direct transmit leakage. By implementingthe RF communication system in this manner, circuitry is reused. Notonly does this reduce cost and/or component count, but also avoidsinserting additional circuitry into the RF signal path that mayotherwise degrade receiver sensitivity and/or transmitter efficiency.

The coexistence management schemes herein can provide a number ofadvantages. For example, the coexistence management schemes can reducean amount of receive filtering and/or transmitter filtering, therebyrelaxing filter constraints and permitting the use of lower costfilters. Furthermore, compensation for RF signal leakage enhancesreceiver sensitivity and/or transmitter efficiency with little to noincrease in power consumption and/or componentry to RF signal paths.Moreover, multiple types of aggressor leakage components can becompensated using common cancellation circuitry, thereby providing acentralized and effective mechanism for coexistence management.

FIG. 2 is a schematic diagram of one example of signal leakage for an RFcommunication system 70. As shown in FIG. 2 , the RF communicationsystem 70 includes a first transceiver 51, a second transceiver 52, afirst front end system 53, a second front end system 54, a first antenna55, and a second antenna 56.

Including multiple transceivers, front end systems, and antennas canenhance the flexibility of the RF communication system 70. For instance,implementing the RF communication system 70 in this manner can allow theRF communication system 70 to communicate using different types ofnetworks, for instance, cellular and WiFi networks.

In the illustrated embodiment, the first front end system 53 includes atransmit front end circuit 61, a receive front end circuit 63, and anantenna access circuit 65, which can include one or more switches,duplexers, diplexers, and/or other circuitry for controlling access ofthe transmit front end circuit 61 and the receive front end circuit 63to the first antenna 55. The second front end system 54 includes atransmit front end circuit 62, a receive front end circuit 64, and anantenna access circuit 66.

Although one example implementation of front end systems is shown inFIG. 2 , the teachings herein are applicable to front end systemsimplemented in a wide variety of ways. Accordingly, otherimplementations of front end systems are possible.

RF signal leakage 69 between the first antenna 55 and the second antenna56 can give rise to a number of coexistence issues. The coexistencemanagement schemes herein provide compensation to reduce or eliminatethe impacts of such RF signal leakage.

FIG. 3A is a schematic diagram of one example of direct transmit leakagefor an RF communication system 80. The RF communication system 80includes a power amplifier 81, a victim receiver 82, a first antenna 83,and a second antenna 84.

In this example, the RF signal outputted from the power amplifier 81serves an aggressor transmit signal that is close in frequency to RFsignals processed by the victim receiver 82. Thus, direct transmitleakage from the aggressor transmit signal gives rise to a degradationin receiver sensitivity.

FIG. 3B is a schematic diagram of one example of regrowth leakage for anRF communication system 90. The RF communication system 90 includes apower amplifier 81, a victim receiver 82, a first antenna 83, and asecond antenna 84.

In this example, the power amplifier 81 receives an RF input signal,which is amplified by the power amplifier 81 to generate an RF outputsignal that is wirelessly transmitted using by the first antenna 83.Additionally, non-linearity of the power amplifier 81 gives rise tospectral regrowth in the RF output signal that is close in frequency toRF signals processed by the victim receiver 82. Thus, regrowth leakagefrom the RF output signal gives rise to a degradation in receiversensitivity.

FIG. 4A is a schematic diagram of an RF communication system 150 withcoexistence management according to one embodiment. The RF communicationsystem 150 includes a first baseband modem 101, a first transceiver 103,a first front end system 105, a first antenna 107, a second basebandmodem 102, a second transceiver 104, a second front end system 106, anda second antenna 108.

In the illustrated embodiment, the first transceiver 103 includes aleakage correction circuit 110, a transmit channel 111, an observationchannel 112, and a receive channel 114. Additionally, the first frontend system 105 includes a transmit front end circuit 115, an observationfront end circuit 116, a receive front end circuit 118, a directionalcoupler 121, and an antenna access circuit 122. Furthermore, the secondtransceiver 104 includes a transmit channel 131, an observation channel132, and a receive channel 134. Additionally, the second front endsystem 106 includes a transmit front end circuit 135, an observationfront end circuit 136, a receive front end circuit 138, a directionalcoupler 141, and an antenna access circuit 142.

Although one embodiment of circuitry for front end systems andtransceivers is shown, the teachings herein are applicable to front endsystem and transceivers implemented in a wide variety of ways.Accordingly, other implementations are possible.

In the illustrated embodiment, the first front end system 105 receivesan RF receive signal from first antenna 107. The RF receive signaltravels through the antenna access component 122 to reach thedirectional coupler 121, which senses the RF receive signal. The sensedsignal by the directional coupler 121 is processed by the observationfront end circuit 116 and the observation channel 112 to generate afirst observation signal, which serves as a first input to the leakagecorrection circuit 110.

With continuing reference to FIG. 4A, baseband transmit data from thesecond baseband modem 102 is provided to the transmit channel 131 of thesecond transceiver 104, which processes the baseband transmit data togenerate an RF input signal to the transmit front end circuit 135. TheRF input signal is processed by the transmit front end circuit 135 togenerate an RF transmit signal that is provided to the second antenna108.

As shown in FIG. 4A, the directional coupler 141 senses the RF transmitsignal outputted by the transmit front end circuit 135. Additionally,the sensed signal by the directional coupler 141 is processed by theobservation front end circuit 136 and the observation channel 132 togenerate a second observation signal, which serves as a second input tothe leakage correction circuit 110.

With continuing reference to FIG. 4A, the RF receive signal from thefirst antenna 107 is also processed by the receive front end circuit 118and downconverted and further processed by the receive channel 114 togenerate a baseband receive signal that serves as a third input to theleakage correction circuit 110.

The leakage correction circuit 110 compensates the baseband receivesignal for RF signal leakage based on the first observation signal andthe second observation signal. Additionally, the leakage correctioncircuit 110 provides a compensated baseband receive signal to the firstbaseband modem 101 for further processing.

In certain implementations, the first observation signal indicates anamount of aggressor spectral regrowth present in the RF receive signalreceived on the first antenna 107, and the second observation signalindicates an amount of direct transmit leakage present in the RFtransmit signal transmitted by the second antenna 108. Thus, the leakagecorrection circuit 110 can serve to provide compensation for multiplecomponents of RF signal leakage, thereby providing a centralized andeffective mechanism for coexistence management.

As shown in FIG. 4A, the first observation signal is generated based ona reverse coupled path to the first antenna 107, and the secondobservation signal is generated based on a forward coupled path to thesecond antenna 108. For example, the first observation signal isgenerated based on the directional coupler 121 sensing an incoming RFsignal from the first antenna 107, while the second observation signalis generated based on the directional coupler 141 sensing an outgoing RFsignal to the second antenna 108.

In certain implementations, the baseband modem 101, the firsttransceiver 103, the first front end system 105, and the first antenna107 handle a first type of RF signals, while the second baseband modem102, the second transceiver 104, the second front end system 106, andthe second antenna 108 handle a second type of RF signals. In oneexample, the first type of RF signals are cellular signals and thesecond type of RF signals are WLAN signals, such as WiFi signals. In asecond example, the first type of RF signals are WLAN signals and thesecond type of RF signals are cellular signals. Although two examples ofRF signal types have been provided, the RF communication system 150 canoperate using other RF signal types. Accordingly, other implementationsare possible.

FIG. 4B is a schematic diagram of an RF communication system 160 withcoexistence management according to another embodiment. The RFcommunication system 160 of FIG. 4B is similar to the RF communicationsystem 150 of FIG. 4A, except that the RF communication system 160illustrates a specific implementation of a leakage correction circuit.

For example, the RF communication system 160 includes a firsttransceiver 153 that includes a discrete time cancellation circuit 151.In the illustrated embodiment, the discrete time cancellation circuit151 receives a first observation signal indicating an amount ofaggressor spectral regrowth present in the RF receive signal received onthe first antenna 107 and a second observation signal indicating anamount of direct transmit leakage present in the RF transmit signaltransmitted by the second antenna 108. The discrete time cancellationcircuit 151 compensates a baseband receive signal received from thereceive channel 114 to generate a compensated baseband receive signal inwhich spectral regrowth and/or direct transmit leakage is reduced and/oreliminated.

The RF communication system 160 of FIG. 4B illustrates one embodiment ofcoexistence management provided by a discrete time cancellation loophaving multiple inputs. The cancellation loop can be adapted to reduceunwanted signal components using any suitable cancellation algorithm.Although one example of a discrete time cancellation loop is shown, theteachings herein are applicable to other implementations of coexistencemanagement. In one embodiment, the discrete time cancellation circuit151 includes a FIR filter having coefficients adapted over time toreduce or eliminate RF signal leakage.

FIG. 5 is a schematic diagram of an RF communication system 170 withcoexistence management according to another embodiment. The RFcommunication system 170 includes a first baseband modem 101, a firsttransceiver 163, a first front end system 165, a first antenna 107, asecond baseband modem 102, a second transceiver 164, a second front endsystem 166, and a second antenna 108.

In the illustrated embodiment, the first transceiver 163 includes adiscrete time cancellation circuit 151, a transmit channel 111, a firstobservation channel 112, a second observation channel 113, and a receivechannel 114. Additionally, the first front end system 165 includes atransmit front end circuit 115, a first observation front end circuit116, a second observation front end circuit 117, a receive front endcircuit 118, a directional coupler 121, and an antenna access circuit122. Furthermore, the second transceiver 164 includes a discrete timecancellation circuit 152, a transmit channel 131, a first observationchannel 132, a second observation channel 133, and a receive channel134. Additionally, the second front end system 166 includes a transmitfront end circuit 135, a first observation front end circuit 136, asecond observation front end circuit 137, a receive front end circuit138, a directional coupler 141, and an antenna access circuit 142.

The RF communication system 170 of FIG. 5 is similar to the RFcommunication system 160 of FIG. 4B, except that the RF communicationsystem 170 is implemented not only to provide discrete time cancellationin the first transceiver 163, but also to provide discrete timecancellation in the second transceiver 164.

For example, with respect to discrete time cancellation in the firsttransceiver 163, the directional coupler 121 senses an incoming RFsignal from the first antenna 107 to generate a sensed signal that isprocessed by the first observation front end circuit 116 and the firstobservation channel 112 to generate a first observation signal for thediscrete time cancellation circuit 151. Furthermore, the directionalcoupler 141 senses an outgoing RF signal to the second antenna 108 togenerate a sensed signal that is processed by the first observationfront end circuit 136 and the first observation channel 132 to generatea second observation signal for the discrete time cancellation circuit151. The incoming RF signal from the first antenna 107 is also processedby the receive front end circuit 118 and the receive channel 114 togenerate a first baseband receive signal, which the discrete timecancellation circuit 151 compensates for RF signal leakage using thefirst observation signal and the second observation signal.

With respect to discrete time cancellation in the second transceiver164, the directional coupler 141 senses the incoming RF signal from thesecond antenna 108 to generate a sensed signal that is processed by thesecond observation front end circuit 137 and the second observationchannel 133 to generate a third observation signal for the discrete timecancellation circuit 152. Furthermore, the directional coupler 121senses an outgoing RF signal to the first antenna 107 to generate asensed signal that is processed by the second observation front endcircuit 117 and the second observation channel 113 to generate a fourthobservation signal for the discrete time cancellation circuit 152. Theincoming RF signal from the second antenna 108 is also processed by thereceive front end circuit 138 and the receive channel 134 to generate asecond baseband receive signal, which the discrete time cancellationcircuit 152 compensates for RF signal leakage using the thirdobservation signal and the fourth observation signal.

FIG. 6 is a schematic diagram of an RF communication system 450 withcoexistence management according to another embodiment. The RFcommunication system 450 includes a cellular antenna 301, a WiFi antenna302, a cellular transceiver 303, a WiFi transceiver 304, a cellularfront end system 305, and a WiFi front end system 306.

Although one embodiment of an RF communication system is shown, theteachings herein are applicable to RF communication systems implementedin a wide variety of ways. For example, an RF communication system caninclude different implementations of antennas, transceivers, and/orfront end systems.

In the illustrated embodiment, the cellular transceiver 303 includes adigital baseband circuit 360 including a cellular transmit basebandsampling circuit 361, a WiFi spectral regrowth baseband sampling circuit362, a cellular transmit power control circuit 363, a discrete timecancellation circuit 381, and a digital receiver 382 that is coupled toa cellular modem (not shown in FIG. 6 ). The cellular transceiver 303operates using Band 7 (B7), in this example.

The cellular transceiver 303 further includes a first observationchannel including a first input amplifier 351 a, a first controllableattenuator 352 a, a first downconverting mixer 353 a, a first low passfilter 354 a, a first post-filtering amplifier 355 a, and a firstanalog-to-digital converter (ADC) 356 a. The cellular transceiver 303further includes a second observation channel including a second inputamplifier 351 b, a second controllable attenuator 352 b, a seconddownconverting mixer 353 b, a second low pass filter 354 b, a secondpost-filtering amplifier 355 b, and a second ADC 356 b. The cellulartransceiver 303 further includes a receive channel including an inputamplifier 371, a downconverting mixer 373, a low pass filter 374, apost-filter amplifier 375, and an ADC 376. As shown in FIG. 6 , anobservation local oscillator (LO) 359 generates an observation LO signalfor providing downconversion in the observation channels, while areceive LO 379 generates a receive LO signal for providingdownconversion in the receive channel.

The cellular front end system 305 includes a diplexer 311, a directionalcoupler 313, and a cellular front end module 315. The cellular front endmodule 315 includes an antenna switch module (ASM) 321, a low noiseamplifier and switches (LNA/SW) 322, a duplexer 323, a power amplifiermodule 324, a control circuit 325, and a transmit input switch 326.

With continuing reference to FIG. 6 , the WiFi transceiver 304 includesa digital baseband circuit 410 including a WiFi transmit basebandsampling circuit 411, a cellular spectral regrowth baseband samplingcircuit 412, a discrete time cancellation circuit 431, and a digitalreceiver 432 that is coupled to a WiFi modem (not shown in FIG. 6 ). TheWiFi transceiver 303 operates using 2.4 GHz WiFi, in this example.

The WiFi transceiver 304 further includes a first observation channelincluding a first input amplifier 401 a, a first controllable attenuator402 a, a first downconverting mixer 403 a, a first low pass filter 404a, a first post-filtering amplifier 405 a, and a first ADC 406 a. TheWiFi transceiver 304 further includes a second observation channelincluding a second input amplifier 401 b, a second controllableattenuator 402 b, a second downconverting mixer 403 b, a second low passfilter 404 b, a second post-filtering amplifier 405 b, and a second ADC406 b. The WiFi transceiver 304 further includes a receive channelincluding an input amplifier 421, a downconverting mixer 423, a low passfilter 424, a post-filter amplifier 425, and an ADC 426. As shown inFIG. 6 , an observation LO 409 generates an observation LO signal forproviding downconversion in the observation channels, while a receive LO429 generates a receive LO signal for providing downconversion in thereceive channel.

As shown in FIG. 6 , a first transceiver-to-transceiver connection 307and a second transceiver-to-transceiver connection 308 provideconnectivity between the cellular transceiver 303 and the WiFitransceiver 304. In certain implementations, the cellular transceiver303 and the WiFi transceiver 304 are a relative far distance from oneanother, and the connections 307-308 include printed circuit board (PCB)trace and/or cables (for instance, cross-UE cables).

The WiFi front end system 306 includes a diplexer 312, a directionalcoupler 314, and a WiFi front end module 316. The WiFi front end module316 includes a transmit/receive switch 341, a power amplifier 342, andan LNA 343.

With continuing reference to FIG. 6 , the directional coupler 313 of thecellular front end system 305 provides sensing of incoming and outgoingRF signals to the cellular antenna 301 travelling along the cellularsignal path 317. Additionally, the directional coupler 314 of the WiFifront end system 306 provides sensing of incoming and outgoing RFsignals to the WiFi antenna 302 travelling along the WiFi signal path318.

The discrete time cancellation circuit 381 of the cellular transceiver303 and the discrete time cancellation circuit 431 of the WiFitransceiver 304 operate in a manner similar to that described above withrespect to FIG. 5 .

FIG. 7 is a schematic diagram of an RF communication system 500 withcoexistence management according to another embodiment. The RFcommunication system 500 of FIG. 7 is similar to the RF communicationsystem 450 of FIG. 6 , except that the RF communication system 500includes a different implementation of a cellular transceiver 451 and ofa cellular front end 455.

Relative to the cellular transceiver 303 of FIG. 6 , the cellulartransceiver 451 of FIG. 7 includes an additional observation pathincluding a third controllable attenuator 352 c, a third downconvertingmixer 353 c, a third low pass filter 354 c, a third post-filteringamplifier 355 c, and a third ADC 356 c. Additionally, the cellulartransceiver 451 further includes an observation selection switch 464,and has a digital baseband circuit 460 that further includes a basebandsampling circuit 461.

The cellular front end system 455 of FIG. 7 is similar to the cellularfront end system 301 of FIG. 6 , except that the cellular front endsystem 455 includes a cellular front end module 465 including adirectional coupler 327 between an output of the power amplifier 324 andan input to the duplexer 323. As shown in FIG. 7 , the directionalcoupler 327 provides a sensed signal to the third observation channel ofthe cellular transceiver 451. The sensed signal is processed by thethird observation channel and the baseband sampling circuit 461 togenerate an observation signal with relatively less group delay effectsrelative to the observation signal generated by the baseband samplingcircuit 361.

In this embodiment, the observation selection switch 464 selectivelyprovides the observation signal from the baseband sampling circuit 461or the observation signal from the baseband sampling circuit 361 to thediscrete time cancellation circuit 381.

By implementing coexistence management in this manner, enhancedreduction of RF signal leakage can be achieved.

FIG. 8 is a schematic diagram of one embodiment of a mobile device 800with coexistence management. The mobile device 800 includes a digitalprocessing system 801, a first transceiver 802, a second transceiver812, a first front end system 803, a second front end system 813, afirst antenna 804, a second antenna 814, a power management system 805,a memory 806, and a user interface 807.

The mobile device 800 can be used communicate using a wide variety ofcommunications technologies, including, but not limited to, 2G, 3G, 4G(including LTE, LTE-Advanced, and LTE-Advanced Pro), 5G NR, WLAN (forinstance, WiFi), WPAN (for instance, Bluetooth and ZigBee), WMAN (forinstance, WiMax), and/or GPS technologies.

In the illustrated embodiment, the digital processing circuit 801includes a first baseband modem 821 and a second baseband modem 822. Incertain implementations, the first baseband modem 821 and the secondbaseband modem 822 control communications associated with differenttypes of wireless communications, for instance, cellular and WiFi. Asshown in FIG. 8 , the first baseband modem 821, the first transceiver802, and the first front end system 803 operate to transmit and receiveRF signals using the first antenna 804. Additionally, the secondbaseband modem 822, the second transceiver 812, and the second front endsystem 813 operate to transmit and receive RF signals using the secondantenna 814. Although an example with two antennas is shown, the mobiledevice 800 can include additional antennas including, but not limitedto, multiple antennas for cellular communications and/or multipleantenna for WiFi communications.

The first front end system 803 operates to condition RF signalstransmitted by and/or received from the first antenna 804. Additionally,the second front end system 804 operates to condition RF signalstransmitted by and/or received from the second antenna 814. The frontend systems can provide a number of functionalities, including, but notlimited to, amplifying signals for transmission, amplifying receivedsignals, filtering signals, switching between different bands, switchingbetween different power modes, switching between transmission andreceiving modes, duplexing of signals, multiplexing of signals (forinstance, diplexing or triplexing), or some combination thereof.

In certain implementations, the mobile device 800 supports carrieraggregation, thereby providing flexibility to increase peak data rates.Carrier aggregation can be used for both Frequency Division Duplexing(FDD) and Time Division Duplexing (TDD), and may be used to aggregate aplurality of carriers or channels. Carrier aggregation includescontiguous aggregation, in which contiguous carriers within the sameoperating frequency band are aggregated. Carrier aggregation can also benon-contiguous, and can include carriers separated in frequency within acommon band or in different bands.

The first antenna 804 and the second antenna 814 can include antennaelements implemented in a wide variety of ways. In certainconfigurations, the antenna elements are arranged to form one or moreantenna arrays. Examples of antenna elements include, but are notlimited to, patch antennas, dipole antenna elements, ceramic resonators,stamped metal antennas, and/or laser direct structuring antennas.

In certain implementations, the mobile device 800 supports MIMOcommunications and/or switched diversity communications. For example,MIMO communications use multiple antennas for communicating multipledata streams over a single radio frequency channel. MIMO communicationsbenefit from higher signal to noise ratio, improved coding, and/orreduced signal interference due to spatial multiplexing differences ofthe radio environment. Switched diversity refers to communications inwhich a particular antenna is selected for operation at a particulartime. For example, a switch can be used to select a particular antennafrom a group of antennas based on a variety of factors, such as anobserved bit error rate and/or a signal strength indicator.

In certain implementations, the mobile device 800 operates withbeamforming. For example, the first front end system 803 and/or thesecond front end system 813 can include phase shifters having variablephase to provide beam formation and directivity for transmission and/orreception of signals. For example, in the context of signaltransmission, the phases of the transmit signals provided to an antennaarray used for transmission are controlled such that radiated signalscombine using constructive and destructive interference to generate anaggregate transmit signal exhibiting beam-like qualities with moresignal strength propagating in a given direction. In the context ofsignal reception, the phases are controlled such that more signal energyis received when the signal is arriving to the antenna array from aparticular direction.

The first transceiver 802 includes one or more transmit channels 831,one or more receive channels 832, one or more observation channels 833,and a discrete time cancellation circuit 834. Additionally, the secondtransceiver 812 includes one or more transmit channels 841, one or morereceive channels 842, one or more observation channels 843, and adiscrete time cancellation circuit 844.

The mobile device 800 of FIG. 8 illustrates one embodiment of a mobiledevice implemented with coexistence management using discrete timecancellation. Although one example of a mobile device is shown, theteachings herein are applicable a wide range of coexistence managementschemes.

The digital processing system 801 is coupled to the user interface 807to facilitate processing of various user input and output (I/O), such asvoice and data. The digital processing system 801 provides thetransceivers with digital representations of transmit signals, which areprocessed by the transceivers to generate RF signals for transmission.The digital processing system 801 also processes digital representationsof received signals provided by the transceivers. As shown in FIG. 8 ,the digital processing system 801 is coupled to the memory 806 offacilitate operation of the mobile device 800.

The memory 806 can be used for a wide variety of purposes, such asstoring data and/or instructions to facilitate the operation of themobile device 800 and/or to provide storage of user information.

The power management system 805 provides a number of power managementfunctions of the mobile device 800. In certain implementations, thepower management system 805 includes a PA supply control circuit thatcontrols the supply voltages of the power amplifiers of the front endsystems. For example, the power management system 805 can be configuredto change the supply voltage(s) provided to one or more of the poweramplifiers to improve efficiency, such as power added efficiency (PAE).

In certain implementations, the power management system 805 receives abattery voltage from a battery. The battery can be any suitable batteryfor use in the mobile device 800, including, for example, a lithium-ionbattery.

FIG. 9A is a schematic diagram of one embodiment of a packaged module900 with coexistence management. FIG. 9B is a schematic diagram of across-section of the packaged module 900 of FIG. 9A taken along thelines 9B-9B.

The packaged module 900 includes radio frequency components 901, asemiconductor die 902, surface mount devices 903, wirebonds 908, apackage substrate 920, and encapsulation structure 940. The packagesubstrate 920 includes pads 906 formed from conductors disposed therein.Additionally, the semiconductor die 902 includes pins or pads 904, andthe wirebonds 908 have been used to connect the pads 904 of the die 902to the pads 906 of the package substrate 920.

The semiconductor die 902 includes an RF communication systemimplemented with discrete time cancellation 941 in accordance with theteachings herein. Although the packaged module 900 illustrates oneexample of a module implemented in accordance with the teachings herein,other implementations are possible.

As shown in FIG. 9B, the packaged module 900 is shown to include aplurality of contact pads 932 disposed on the side of the packagedmodule 900 opposite the side used to mount the semiconductor die 902.Configuring the packaged module 900 in this manner can aid in connectingthe packaged module 900 to a circuit board, such as a phone board of awireless device. The example contact pads 932 can be configured toprovide radio frequency signals, bias signals, and/or power (forexample, a power supply voltage and ground) to the semiconductor die902. As shown in FIG. 9B, the electrical connections between the contactpads 932 and the semiconductor die 902 can be facilitated by connections933 through the package substrate 920. The connections 933 can representelectrical paths formed through the package substrate 920, such asconnections associated with vias and conductors of a multilayerlaminated package substrate.

In some embodiments, the packaged module 900 can also include one ormore packaging structures to, for example, provide protection and/orfacilitate handling. Such a packaging structure can include overmold orencapsulation structure 940 formed over the packaging substrate 920 andthe components and die(s) disposed thereon.

It will be understood that although the packaged module 900 is describedin the context of electrical connections based on wirebonds, one or morefeatures of the present disclosure can also be implemented in otherpackaging configurations, including, for example, flip-chipconfigurations.

APPLICATIONS

Some of the embodiments described above have provided examples inconnection with mobile devices. However, the principles and advantagesof the embodiments can be used for any other systems or apparatus thathave needs for coexistence management. Examples of such RF communicationsystems include, but are not limited to, mobile phones, tablets, basestations, network access points, customer-premises equipment (CPE),laptops, and wearable electronics.

CONCLUSION

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,” and thelike are to be construed in an inclusive sense, as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to.” The word “coupled”, as generally usedherein, refers to two or more elements that may be either directlyconnected, or connected by way of one or more intermediate elements.Likewise, the word “connected”, as generally used herein, refers to twoor more elements that may be either directly connected, or connected byway of one or more intermediate elements. Additionally, the words“herein,” “above,” “below,” and words of similar import, when used inthis application, shall refer to this application as a whole and not toany particular portions of this application. Where the context permits,words in the above Detailed Description using the singular or pluralnumber may also include the plural or singular number respectively. Theword “or” in reference to a list of two or more items, that word coversall of the following interpretations of the word: any of the items inthe list, all of the items in the list, and any combination of the itemsin the list.

Moreover, conditional language used herein, such as, among others,“may,” “could,” “might,” “can,” “e.g.,” “for example,” “such as” and thelike, unless specifically stated otherwise, or otherwise understoodwithin the context as used, is generally intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements and/or states. Thus, such conditional language is notgenerally intended to imply that features, elements and/or states are inany way required for one or more embodiments or that one or moreembodiments necessarily include logic for deciding, with or withoutauthor input or prompting, whether these features, elements and/orstates are included or are to be performed in any particular embodiment.

The above detailed description of embodiments of the invention is notintended to be exhaustive or to limit the invention to the precise formdisclosed above. While specific embodiments of, and examples for, theinvention are described above for illustrative purposes, variousequivalent modifications are possible within the scope of the invention,as those skilled in the relevant art will recognize. For example, whileprocesses or blocks are presented in a given order, alternativeembodiments may perform routines having steps, or employ systems havingblocks, in a different order, and some processes or blocks may bedeleted, moved, added, subdivided, combined, and/or modified. Each ofthese processes or blocks may be implemented in a variety of differentways. Also, while processes or blocks are at times shown as beingperformed in series, these processes or blocks may instead be performedin parallel, or may be performed at different times.

The teachings of the invention provided herein can be applied to othersystems, not necessarily the system described above. The elements andacts of the various embodiments described above can be combined toprovide further embodiments.

While certain embodiments of the inventions have been described, theseembodiments have been presented by way of example only, and are notintended to limit the scope of the disclosure. Indeed, the novel methodsand systems described herein may be embodied in a variety of otherforms; furthermore, various omissions, substitutions and changes in theform of the methods and systems described herein may be made withoutdeparting from the spirit of the disclosure. The accompanying claims andtheir equivalents are intended to cover such forms or modifications aswould fall within the scope and spirit of the disclosure.

What is claimed is:
 1. A mobile device comprising: a wireless local areanetwork transceiver including a wireless local area network observationchannel configured to process a wireless local area network observationsignal to generate wireless local area network observation data; and acellular transceiver including a cellular receive channel configured toprocess a radio frequency cellular receive signal to generate a digitalbaseband cellular receive signal, a cellular observation channelconfigured to process a cellular observation signal to generate cellularobservation data, and a discrete time cancellation circuit configured tocompensate the digital baseband cellular receive signal for radiofrequency signal leakage based on the wireless local area networkobservation data and on the cellular observation data.
 2. The mobiledevice of claim 1 further comprising a wireless local area network frontend system configured to generate the wireless local area networkobservation signal based on observing a wireless local area networktransmit signal.
 3. The mobile device of claim 2 wherein the wirelesslocal area network front end system includes a directional couplerconfigured to generate the wireless local area network observationsignal based on sensing the wireless local area network transmit signal.4. The mobile device of claim 3 further comprising an antenna, thedirectional coupler configured to generate the wireless local areanetwork observation signal based on a forward coupled path to theantenna.
 5. The mobile device of claim 2 wherein the wireless local areanetwork observation data indicates an amount of direct transmit leakagepresent in the wireless local area network transmit signal.
 6. Themobile device of claim 1 further comprising a cellular front end systemconfigured to generate the cellular observation signal based onobserving a cellular transmit signal.
 7. The mobile device of claim 6wherein the cellular front end system includes a directional couplerconfigured to generate the cellular observation signal based on sensingthe cellular transmit signal.
 8. The mobile device of claim 7 furthercomprising an antenna, the directional coupler configured to generatethe cellular observation signal based on a reverse coupled path to theantenna.
 9. The mobile device of claim 7 wherein the cellular front endsystem includes a duplexer, the directional coupler positioned betweenan output of the duplexer and the antenna.
 10. The mobile device ofclaim 7 wherein the cellular front end system includes a duplexer and apower amplifier, the directional coupler positioned between an output ofthe power amplifier and an input to the duplexer.
 11. The mobile deviceof claim 1 wherein the wireless local area network transceiver is a WiFitransceiver.
 12. A method of coexistence management in a mobile device,the method comprising: processing a wireless local area networkobservation signal to generate wireless local area network observationdata using a wireless local area network observation channel of awireless local area network transceiver; processing a radio frequencycellular receive signal to generate a digital baseband cellular receivesignal using a cellular receive channel of a cellular transceiver;processing a cellular observation signal to generate cellularobservation data using a cellular observation channel of the cellulartransceiver; and compensating the digital baseband cellular receivesignal for radio frequency signal leakage based on the wireless localarea network observation data and on the cellular observation data usinga discrete time cancellation circuit of the cellular transceiver. 13.The method of claim 12 further comprising generating the wireless localarea network observation signal based on observing a wireless local areanetwork transmit signal using a wireless local area network front endsystem.
 14. The method of claim 13 further comprising generating thewireless local area network observation signal based on sensing thewireless local area network transmit signal using a directional coupler.15. The method of claim 14 further comprising using the directionalcoupler to generate the wireless local area network observation signalbased on a forward coupled path to an antenna.
 16. The method of claim13 further comprising generating the wireless local area networkobservation data to indicate an amount of direct transmit leakagepresent in the wireless local area network transmit signal.
 17. Themethod of claim 12 further comprising generating the cellularobservation signal based on observing a cellular transmit signal using acellular front end system.
 18. The method of claim 17 further comprisinggenerating the cellular observation signal based on sensing the cellulartransmit signal using a directional coupler.
 19. A cellular transceivercomprising: a cellular receive channel configured to process a radiofrequency cellular receive signal to generate a digital cellularbaseband receive signal; an input configured to receive wireless localarea network observation data from a wireless local area networktransceiver; an observation channel configured to process a cellularobservation signal to generate cellular observation data; and a discretetime cancellation circuit configured to compensate the digital basebandcellular receive signal for radio frequency signal leakage based on thewireless local area network observation data and on the cellularobservation data.
 20. The cellular transceiver of claim 19 wherein thewireless local area network observation data indicates an amount ofdirect transmit leakage present in a wireless local area networktransmit signal.